1. Field of the Invention
The invention relates to bone distractive and contractive movements and more particularly, to apparatus and methods for the correction of craniofacial bone deformities.
2. Description of Related Technology
Human children born with skull and facial (craniofacial) bone growth disorders known as craniosynostosis develop profound abnormalities in the shape and function of the craniofacial skeleton. The underlying causative factor is the congenital absence of anatomically normal sutures (lines of open bone) between the various segments of craniofacial bone. This fusion of the normal bone lines, or synostosis, leads to unbalanced bone growth and subsequent deformation. The traditional treatment for these disorders has been surgical exposure, and transfer of the bones to create a more normal architecture. Such surgery requires neurosurgical exposure of the brain and its surrounding tissues. Also, bone grafts, plating, wires, and other rigid fixation implants are required to stabilize the repositioned bones.
Alternative methods for correcting synostotic deformities in young infants without the risk of major intracranial surgery and bone grafts have been introduced. For example, Remmler, U.S. Pat. No. 5,147,358 discloses an apparatus which was utilized to gradually reposition the cranial and fronto-facial bones in a rabbit model by mechanical means to a degree proportionate to that required in humans with craniosynostosis. Stainless steel fixation plates with threaded tubes were attached with screws to the craniofacial bones. Next, threaded percutaneous (through the skin) pins were attached to the plates. The bones were then gradually repositioned over a period of approximately one and one-half months to the desired position using an external jackscrew mechanism.
The device disclosed in U.S. Pat. No. 5,147,358 has been used to successfully distract bone segments primarily in one dimension. However, congenital craniofacial anomalies are frequently asymmetric in three dimensions, requiring simultaneous distractive and contractive movements of multiple major bone segments. Thus, a need exists for a versatile, multi-axial apparatus, system, and method for moving multiple bone segments in various directions.